KAKTOVIK, Alaska — Come fall, polar bears are everywhere around this Arctic village, dozing on sand spits, roughhousing in the shallows, padding down the beach with cubs in tow and attracting hundreds of tourists who travel long distances to see them.

At night, the bears steal into town, making it dangerous to walk outside without a firearm or bear spray. They leave only reluctantly, chased off by the polar bear patrol with firecracker shells and spotlights.

On the surface, these bears might not seem like members of a species facing possible extinction.
Scientists have counted up to 80 at a time in or near Kaktovik; many look healthy and plump, especially in the early fall, when their presence overlaps with the Inupiat village’s whaling season.

But the bears that come here are climate refugees, on land because the sea ice they rely on for hunting seals is receding.

The Arctic is warming twice as fast as the rest of the planet, and the ice cover is retreating at a pace that even the climate scientists who predicted the decline find startling.

Much of 2016 was warmer than normal, and the freeze-up came late. In November, the extent of Arctic sea ice was lower than ever recorded for that month. Though the average rate of ice growth was faster than normal for the month, over five days in mid-November the ice cover lost more than 19,000 square miles, a decline that the National Snow and Ice Data Center in Colorado called “almost unprecedented” for that time of year.

In the southern Beaufort Sea, where Kaktovik’s 260 residents occupy one square mile on the northeast corner of Barter Island, sea ice loss has been especially precipitous.

The continuing loss of sea ice does not bode well for polar bears, whose existence depends on an ice cover that is rapidly thinning and melting as the climate warms. As Steve Amstrup, chief scientist for Polar Bears International, a conservation organization, put it, “As the sea ice goes, so goes the polar bear.”
http://www.nytimes.com/2016/12/18/science/polar-bears-global-warming.html